The present invention relates to a method of curing a synthetic resin impregnant in a porous cellulosic material, such as wood, by means of a heated curing medium in the presence or absence of a curing catalyst.
Curing of synthetic resin impregnants in wood by means of heat is conventional. The curing temperature depends primarily on the catalyst used. The curing reaction is exothermic and, if the impregnated body is not very thin, the temperature in the interior thereof often rises during the reaction to the point where the interior surfaces are scorched and the material may even split. Attempts have been made to avoid this, for instance by carrying out the polymerization of the synthetic resin impregnant in presses whose working surfaces serves to carry the heat of reaction to and from the material. One disadvantage of using presses is that the procedure can be carried out in practice only in the case of plate-like bodies. In addition, the procurement costs of presses are high.
It has been also proposed to use gas current for heating and cooling the impregnated material but they bring about a marked volatilization of the resin forming liquid impregnant, and particularly from the surface of the impregnated body, resulting in a poor surface quality. The transfer of heat into the impregnated material is slow so that a long heating time is required. In addition, the recovery of volatilized impregnant and cooling the gas considerably increase the cost of the process.